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Two of the sharks were caught in the Bay of Edremit, Turkey, two years ago. The third was found off Tunisia in 2006 and the fourth off Sicily 20 years ago.

The original journey to Europe was probably made by a few pregnant females as long as 450,000 years ago, according to the scientists.

They may have taken a ‘wrong turn’ due to a number of factors including climate change, high sea levels and unusual ocean eddy-currents called Agulhas rings.

The warm Agulhas Current flows down the east coast of Africa, but sometimes an Agulhas ring carries its waters around the southern tip of the continent and into the Benguela Current off the west coast of South Africa.

A group of sharks swimming in one of these bubbles could miss the turning and find the western coast of Africa between it and its destination.

'Konyaalti' beach in Antalya, Turkey. Great white sharks found off the Turkish coast may have taken a wrong turn on the way back from Africa

Scientists already knew that sharks frequently swim between Australia and Africa, and navigate by following currents.

In this case, instead of returning home from Africa, the sharks are believed to have continued heading west.

They may have been led astray by Agulhas rings which, due to climate change at the time, would have been much more powerful than they are today.

Only after entering the Atlantic Ocean and becoming free of the currents would the sharks have turned around. But by then their path would have been blocked by the west coast of Africa.

Following the coast eastwards they would eventually have reached the Straits of Gibraltar, and the mouth of the Mediterranean.

Swordfish and bluefin tuna - food for the great whites - are thought to have arrived in the Mediterranean the same way.

The findings are published today in the journal Proceedings of the Royal Society B.

Dr Cathy Jones, a shark geneticist from the University of Aberdeen's School of Biological Sciences, said: ‘We discovered that genetically Mediterranean white sharks are effectively a displaced Australian population which was probably a consequence of a historical navigational error by a few pregnant females during a time of global climate change.

‘Once they got to the Mediterranean they may have become trapped because its peninsulas and channels make it like a giant lobster pot.’

Colleague Dr Chrysa Gubili said: ‘It is an incredible journey that we believe is historical and not happening now, but was prompted by a period of climatic instability.

‘Some might say they could have entered the Med via the Suez Canal, but this apparently obvious route is unlikely because of high temperatures and hypersalinity.’

Dr Noble said the Mediterranean great whites were now an endangered population which needed protection.

‘They are big fish in a small pond and are at the top of the food chain in a sea where they have moulded the ecosystem,’ he added.